Đáp án:
$\begin{array}{l}
\lim \dfrac{{2 - {5^{n - 2}}}}{{{3^n} - {{2.5}^n}}}\\
= \lim \dfrac{{2 - \dfrac{1}{{25}}{{.5}^n}}}{{{3^n} - {{2.5}^n}}}\\
= \lim \dfrac{{\dfrac{2}{{{5^n}}} - \dfrac{1}{{25}}}}{{\dfrac{{{3^n}}}{{{5^n}}} - 2}}\\
= \dfrac{{\dfrac{{ - 1}}{{25}}}}{{ - 2}} = \dfrac{1}{{50}}
\end{array}$